The present invention relates to a novel process for producing compositions for ruminants in which an aqueous suspension is used for coating.
In ruminants, substances orally administered are stored in the rumen of pH 5.5 and then absorbed into a blood stream in the abomasum of pH 3.0.
In order to increase the absorption of physiologically active substances in the abomasum, there have been developed compositions for ruminants utilizing coating materials which have a suppressive effect on the decomposition of the active substances in the rumen, but do not have a suppressive effect on the absorption of the active substances in the abomasum.
For example, Japanese Published Unexamined Patent Application Nos. 88843/86, 88844/86 and U.S. Pat No. 5,080,917 (EP-A-336,713) disclose compositions which comprise as a coating a hydrophobic substance hardly soluble in water of pH 5.5 or above and a polymer soluble in water of pH 5.0 or below. The compositions are produced by coating a granulated physiologically active substance as a nucleus with a coating material by spraying. The coating material is prepared by dissolving a hydrophobic substance hardly soluble in water of pH 5.5 or above and a polymer soluble in water of pH 5.0 or below in an organic solvent. During the spray coating, a large quantity of the organic solvent evaporates and diffuses into the air. Such process involves the danger of pollution and fire.
Therefore, it is desired to develop a process for producing compositions for ruminants which does not involve such problem.